TITLE:
Comparative Analysis of the Exon-Intron Structure in Eukaryotic Genomes
AUTHORS:
Yongfa Li, Yanhua Xu, Zhaowu Ma
KEYWORDS:
Exon-Intron Structure, Eukaryotic Genome, Evolution
JOURNAL NAME:
Yangtze Medicine,
Vol.1 No.1,
March
30,
2017
ABSTRACT: The exon numbers and lengths vary in different eukaryotic species. With increasing completed genomic sequences, it is indispensable to reanalyze the gene organization in diverse eukaryotic genomes. We performed a large-scale comparative analysis of the exon-intron structure in 72 eukaryotic organisms, including plants, fungi and animals. We confirmed that the exon-intron structure varies massively among eukaryotic genomes and revealed some lineage-specific features of eukaryotic genes. These include a teleost-specific exon-intron structure pattern, relatively small introns and large exons in fungi and algae, and a gradual expansion of introns in vertebrates. Furthermore, the conservation analysis of exon-intron boundaries indicates that several bases near splice site junctions are different in introns with variable length among different species. After comparison, we identified a trend showing increases in intron densities and lengths in diverse species from fungi, plants, invertebrates to vertebrates, while it was the opposite in relation to exon lengths. The statistical properties of eukaryotic genomic organization suggest that genome-specific features are preserved by diverse evolutionary processes, which paves way for further research on the diversification of eukaryotic evolution.